package org.apache.lucene.util;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.LucenePackage;

/**
 * Some useful constants.
 **/

public final class Constants {
    private Constants() {
    } // can't construct

    /** The value of <tt>System.getProperty("java.version")<tt>. **/
    public static final String JAVA_VERSION = System.getProperty("java.version");

    /** True iff this is Java version 1.1.
     * @deprecated This constant is useless since Lucene is on Java 5 */
    @Deprecated
    public static final boolean JAVA_1_1 = JAVA_VERSION.startsWith("1.1.");
    /** True iff this is Java version 1.2.
     * @deprecated This constant is useless since Lucene is on Java 5 */
    @Deprecated
    public static final boolean JAVA_1_2 = JAVA_VERSION.startsWith("1.2.");
    /** True iff this is Java version 1.3.
     * @deprecated This constant is useless since Lucene is on Java 5 */
    @Deprecated
    public static final boolean JAVA_1_3 = JAVA_VERSION.startsWith("1.3.");

    /** The value of <tt>System.getProperty("os.name")<tt>. **/
    public static final String OS_NAME = System.getProperty("os.name");
    /** True iff running on Linux. */
    public static final boolean LINUX = OS_NAME.startsWith("Linux");
    /** True iff running on Windows. */
    public static final boolean WINDOWS = OS_NAME.startsWith("Windows");
    /** True iff running on SunOS. */
    public static final boolean SUN_OS = OS_NAME.startsWith("SunOS");
    /** True iff running on Mac OS X */
    public static final boolean MAC_OS_X = OS_NAME.startsWith("Mac OS X");

    public static final String OS_ARCH = System.getProperty("os.arch");
    public static final String OS_VERSION = System.getProperty("os.version");
    public static final String JAVA_VENDOR = System.getProperty("java.vendor");

    public static final boolean JRE_IS_64BIT;
    public static final boolean JRE_IS_MINIMUM_JAVA6;
    public static final boolean JRE_IS_MINIMUM_JAVA7;
    static {
        // NOTE: this logic may not be correct; if you know of a
        // more reliable approach please raise it on java-dev!
        final String x = System.getProperty("sun.arch.data.model");
        if (x != null) {
            JRE_IS_64BIT = x.indexOf("64") != -1;
        } else {
            if (OS_ARCH != null && OS_ARCH.indexOf("64") != -1) {
                JRE_IS_64BIT = true;
            } else {
                JRE_IS_64BIT = false;
            }
        }

        // this method only exists in Java 6:
        boolean v6 = true;
        try {
            String.class.getMethod("isEmpty");
        } catch (NoSuchMethodException nsme) {
            v6 = false;
        }
        JRE_IS_MINIMUM_JAVA6 = v6;

        // this method only exists in Java 7:
        boolean v7 = true;
        try {
            Throwable.class.getMethod("getSuppressed");
        } catch (NoSuchMethodException nsme) {
            v7 = false;
        }
        JRE_IS_MINIMUM_JAVA7 = v7;
    }

    // this method prevents inlining the final version constant in compiled classes,
    // see: http://www.javaworld.com/community/node/3400
    private static String ident(final String s) {
        return s.toString();
    }

    // NOTE: we track per-segment version as a String with the "X.Y" format, e.g.
    // "4.0", "3.1", "3.0". Therefore when we change this constant, we should keep
    // the format.
    public static final String LUCENE_MAIN_VERSION = ident("3.5");

    public static final String LUCENE_VERSION;
    static {
        Package pkg = LucenePackage.get();
        String v = (pkg == null) ? null : pkg.getImplementationVersion();
        if (v == null) {
            v = LUCENE_MAIN_VERSION + "-SNAPSHOT";
        } else if (!v.startsWith(LUCENE_MAIN_VERSION)) {
            v = LUCENE_MAIN_VERSION + "-SNAPSHOT " + v;
        }
        LUCENE_VERSION = ident(v);
    }
}
